Decorative Ironwork Part 1_tcm2-18947

8/7/2019 Decorative Ironwork Part 1_tcm2-18947

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Decorative Ironwork


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Other publications available:The blacksmith's craftISBN [ 869964 14 4Blacksmith's manual illustratedISBN 1 869964 21 7Metals for engineering craftsmenISBN 0 854070 27 3Wrought ironworkISBN 0 854070 07 9Catalogue of drawings for wrought ironworkISBN 0 854070 28 ICatalogue of drawings - wrought ironwork gatesISBN 1 869964 22 5Catalogue of drawings - weathervanesISBN I 869964 28 4For publications please contact:Countryside Agency PublicationsPO Box 125, Wetherby, West Yorkshire LS23 lEP ,Tel: 0870 1206446Fax: 0870 1206467Website: www.countryside.gov.ukMinicom: 0870 1207405 (for the hard of hearing)
http://www.countryside.gov.uk/http://www.countryside.gov.uk/


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Decorative Ironworksome aspects of design and technique

-The Countryside~Agency


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Flr;L published 1'162Rrprrntcd LW,u, 1966Rcpr intcd 1969Repr mted 1973Repr uued 197HRvprnned 1987

'-. Council for Sural! Induvtric in Rural ,\rea'ISBN a RqOi I J I 2 S

Rcprmtcd WOO

') Th~ Coumrvvrdc AgeIlt)ISA'.J 086170632 3CAn

I\nL"h Librar , CIP DaLa,_" l~La logue record for th " book rs availahle frum L Ii" B riLL ,]ILibrary,

,-\11n~ht, rc,cned, No pari of this puhlnation I1la) hi, reproduu-d. storedin d retrieval "}':'1tenl, or transmiucd 111 anv form or n~ '.Illy means,~lt'


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ContentsIntroductionDesign 1Design 2Design 3Design 4Design 5

Design 6Design 7Index .....Conversions .

.. 7.. 9.17

.31

.43

.49

.61 .69

.78........... 80


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Decorative Ironwork - some aspects of design and techniqueThis is the third technical book on the subject ofblacksmithing to be published by the CountrysideAgency and its predecessor bodies. It has beencarefully reproduced in its original format to retainthe appeal of the original text. photographs anddrawings that have for so long proved to be avaluable source of reference.The information contained in this book is aimed atthe specialist ironworker and will assist trainees togain a better understanding of their craft.

The Countryside Agency offers a wide range ofcourses and related publications as part of itsresponsibility to develop rural skills that can enhancethe environment and preserve the character andcultural heritage of the countryside. We run a ruralforgework apprenticeship and short courseprogramme covering more specific techniques.Courses are offered at different levels and includegeneral smithing, scroll work, fitting and framework.power hammer work and tool making. lead blockrepousse, gilding and decorative effects.


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INTRODUCTIONThis is the third manual on the subject of blacksmithing to bepublished by the Council for Small Industries in Rural Areas.The first, The Blscksmittvs Craft, dealing with basic and general

smithing, was followed by Wrought Ironwork, a technical work inwhich the basic elements of the decorative side of the smith'scraft were descri bed.In both these works great attention was paid to technical detail

throughout the profusely illustrated texts. To a large degree theywere complementary and were add res sed to the novice as wellas the more advanced smith.This third volume has, however, been compiled more with the

specialist ironworker in mind. Consequently, a number of opera-tions incl uded under the head ing of standard practice have notbeen described in detail, asthis would have proved unnecessarilytedious to the skilled smith, and would also have tended to divertthe aim of the book.The purpose of the authors was, broadly speaking, threefold.First to introduce a number of methods of working iron not

normally found in association with scroll work; methods in factdissimilar to those commonly employed in this country since theearly 1Sth century, but lending themselves more readily to designsakin in character to work executed prior to that period.Secondly, to suggest to craftsmen by mean s of certain of these

methods or techniques, that a return to a form of design in which7


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flat metal surfaces, rather than narrow edges, are more promin-ently displayed, might tend to produce ironwork better suited tosome styles of modern architecture.In relation to the latter point, it was felt that the style of modern

continental Ironwork, in which similar technical methods havebeen exploited for some considerable time, would eventually bebound to influence patrons of the craft in this country. Untilrecently, designs copied or derived from the 18th century mannerhave been generally acceptable in Britain, but with the upsurgeof continental travel the need for greater flexibility in ideas mightarise.This possibility materially affected the selection of techniques

dealt with in this volume. They were chosen with the object ofdemonstrating to the craftsman and designer that quite a smallnumber of 'moves' can yield a wider range of possibilities indesign than might bo expected. In this connection grilles Nos.3 and 4 afforded an interesting example of identical methodsproducing, simply by the change in direction of a chisel cut, twodesigns similar in structural form but differing widely in orna-menta! effect. The inclusian of more examples of this kind wasconsidered undesirable if the third aim of the book was to beachieved.Thus, thirdly, it was hoped that the manner in which the tech-

nical material was presented would prompt those receptive ofnew ideas to enter the experimental field through the medium 0 1design, and create for themselves.The exploitation of a technique for its own sake arone is liable

to give rise to departures from established practice merely toachieve novel or ingen ious effects: such results are withoutmerit and it is for the avoidance of this fatal error that the designfactor is stressed here and at intervals throughout the text.Though working drawings of each grille have been produced

and are available to rural smiths, the grilles should not be re-garded simply as catalogue designs, but rather as examples tobe studied one in conjunction with another.Betore any attempt is made to use an individual text as a working

recipe, the volume should be read, as Initially intended, fromcover to cover. For good reasons certain details were dealt withat the ends of the chapters, while other material points mentionedin the text applying to one example may throw additional light onprocesses applicable to one or more of the other designs. Thusit was hoped that the reader would, by following the text con-secutively, develop a mental picture of the subject as a whole,before becoming preoccupied with specific details.The examples have been called 'grilles' for convenience andnot because the repeating designs employed are suitable for the

making of grilles only, or to suggest that the decorative featuresmust necessarily fill any given framework. Several of the devicesmight well be used sparingly in large gates, for example, in theform of borders or panels, so long as the overall character of thework is maintained; in fact the techniques dealt with in this bookcan be applied over the whole field of decorative ironwork.8


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Design 1A feature of this design Is the exploitation of contrasting barsections. The use of rectangular section for one series of bars,and a round section for the other series, not only appeals to theeye, but also simplifies the making of the apertures in the flatbars through which the round bars pass.The method employed eliminates the hot punching, driftingand dressi ng associated with intersecting bar work, and conse-quently saves time.The lack of ability to fire weld is no handicap in the construction

of this particular grille as the simple leaf forms are not madeseparately and attached, but are developed from the parent barby methods which have, particularly since the 18th century,largely fallen into disuse in this country.It will be appreciated that this design may be carried out in a

wide range of bar.sizes. Because the use of the chisel gives riseto a limited amount of drawing of the metal, and since the lengthof slit required to form an eye of given size must be determined,deflnite bar sizes are quoted and dimensions given. These figuresare used solely for the purpose of rendering technical principlesclear, and apply to 1~' X iN and ~. round bar.The frame size of this particular example is 3' 9' x 2' 10;N and

is made from 1 N x ~ N bar.

9


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DESIGN 1

Fig 1 The flat bar is marked out with chisel and centre pu nch. Thedrawing, Fig. 16 on page 16, gives the measurements for settingout when using 1r :-:ff bar.This marking, besides being accurate must be sufficientlyindented to be seen clearly when the metal has been heated forslitting and cutting operation.

Fig 2 A slit is cut in the hot metal with a chisel + r wide, this being theslit necessary for the formation of an eye through which ;." roundbar will pass.A cutting plate, preferably of copper, is used to protect the

chisel edge from the hardened anvil face.Fig 3 Using a ;" top fuller in conjunction with 1" bottom swage, one half

of the eye is formed.A bottom swage of ample depth must be used if pinching-in

the bottom of the tool and consequent malformation of the shapeis to be avoided.The bar is turned over and the other half eye is formed.Assuming that no unnecessary violence has been used, it will

be found in practice that no appreciable alteration occurs in thedistance between centres. which in the present case is 7b', asshown in the diagram on page 16.It is important to use a hand length of ~"round bar to check that

eyes have been opened sufficiently to enable the 10 nger rou ndbars to pass th ro ug h a series of eyes easily when the work isassembled.

Note: The setting of the eyes alternates. A scrutiny of the illus-tration of the finished grille will make this point clear.

Fig 4 A curved chisel is used to release the tip of the spur, and thestraight cut is continued with a sharp hot-set.It is here, in this operation, that a slight lengthening can occur.

To minimise this effect, the hot-set must be thin and a good edgemust be maintained.From tip to butt the spur must be released progressively with

well-controlled blows of a moderate weight.I n order that the natural chamfer made by the hot-set may appear

10


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Fig. 4

uniformly on the face side of the work, all cutti ng must be donefrom one side only.From time to time work must be checked to ensure that the

measurements between the centres of the eyes is uniform.

Fig. 311


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DESIGN 1

Fig 5 The reason for the next step may not be obvious at this stage.It will suffice to state here that on it depends the correct formationand setting of the spurs. By carefully following the instructionsfor the succeeding operations the reason for this first step willbecome apparent.The spur is given a short 90' twist bringing its outside edge

uppermost in relation to the face side of the bar. In order to facili-tate this operation the spur is first pulled out at a convenientangle.

Fig 5 The 90: short twist is made and this brings the curve of the spurtip into a position which assists when further curving the featureas forging proceeds.The bar is gripped in the vice with the eye inserted a short

distance within the jaws. This ensures stability and preventsdi stortion.

Fig 7

Fig 8

Fig 9

Fig 10

Using a curved faced hammer the twist is dressed 10 blend withan even flow into the main bar. If necessary the heat should belocalised by controlled quenching to avoid distortion occurringeither in the eye or the centre stem.

The twisted root of the spur is dressed on two sides roug hly atright angles to one another in order to produce a uniform section.As it IS clearly impossible to continue on the anvil bick, a stakewith an acute angled flat IS bro ught into use.

The spur is now curved over the bick, care being taken to avoidcontinuing this operation too far, as further curving takes placenaturally during the stages to follow.It is also convenient at this point to ref ne the shape of the sp ur

tip a little, bearing in mind that a few light blows will suffice, asany tendency to depart from the leaf form is out of place in thisdesign.

With the spur resting flat on the anvil both edges are hammerchamfered. A curved faced hammer is used for treating the inner

12


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Fig. 9 Fig. 10

Fig. 6


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Fig 11

Fig 12

Fig 13

Figs 14and 15

DESIGN 1

edge and a flat faced hammer 10r the outer. and the transformationfrom the spur into the leaf form develops.The leaf form is still lying in a place at right angles to the face ofthe bar.At this stage, however, the axis of the leaf is canted by resting

the inside edge on the bick. The outside edge is therefore raiseda little and is hammered down on to the bick with light coaxrnqblows, great care being exercised to avoid solid blows whichwould thin the metal and tend to distort the emerging shape.This action is used progressively from tip to butt, the work

being moved round the bick as shaping proceeds.During this operation the leaf begins to revert to its original

plane, moving back through the 90' setting described in Fig 5.Additional work is still required to bring the leat right back intoa plane true with the parent bar.This is done by gripping the top edge of the leaf with the round-

nosed pliers at a point where leverage applied in a downwarddirection will bring the leaf into its correct setting.This motion achieves two objects. First the leaf is set in itscorrect plane, and, secondly, the top edge is correctly canted

and blended with a smoath sweep into the parent bar to completethe flow of the whole form.After a pair of leaves has been forged they are given the custom-ary inspection and any small adjustment is made. Nothing morethan a light tap here and there with the hand hammer will usuallybe necessary.Assuming that the frame has been made to the required dimens-ions, and all the decorative bars have been forged, work prepara-tory to assembly begins.Using the ful! size working drawing for guidance, the forged bars

are placed accurately on the frame and round bars are tempor-arily passed through the eyes to check alignment. The cutting-offpoints are marked at the correct angles on the flat bars wherejunction is made with the frame.14


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Fig. 13

Fig. 15

Fig . 12

Fig, 14


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/% I1 _ - t < _ j

Fig. 16 MarKing out diagramAfter cutting to length the ends are shaped and hammer

chamfered.Tile position s of rivet holes are now marked and clearanceholes drilled.The bars are reassembled on the frame over the working

drawinq, and the rive! holes are scribered through on to theframe. These holes are now drilled and slightly countersunkat the back.The bars are fixed into position temporarily With bolts and nuts

which are replaced eventually by rivets.For ease of working, the ro und bars whic h have forged bosses

drilled tor riveting at either end, are each made in two sectionsand oxy-acetylene weld ed together when in place. The buttjoints must be arranged to fall in convenient positions betweenthe decorative bars.Where the bars of the grille abut the frame, a number of half

squares occur naturally. They do not afford sufficient space toaccom modate the leaf motif in the form used in the com pletesquares. Consequently a leaf of a different shape was designedto fill these triangular spaces. These leat forms were producedfrom spurs released from the bar in the same manner as the mainleaf motif, and were worked in a Similar way, but were shaped tosuit the proportions ot the space to be filled.To ensure the full e~ct of this design reasonably precise

adherence to the full size working drawing must be maintained:nevertheless work should be freely forged and the direct characterof the hammer work should not be spoiled by unnecessary feUli ng.When assembling it may be found helpful to use a round file

for easing the sides of the eyes through which the straight;'round bars pass, should adjustment of alignment be necessary.As one of the fixi ng holes in each of the flat bar-end s is also

used for the fixing point of a round bar, the ends of the latter areset and cranked so that their rivet holes, when drilled, will becentral in the bosses and coincide with the appropriate holes.Ii it is desired to use this design ior a gate. the complete grille

could be housed within another frame made in the usual mannerfor gates, carrying the appropriate fittings. This would becomea shadow surround, the grille being secured by countersunkscrews.

16


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Design 2The design of this example deviates from the orthodox in the waythat the decorative features are evolved from the structural barsof the grille and are not additions in the form of branch welded orcollared scrollwork.Such scrollwork and other applied ornamental devices have

been used for generations to form panels and borders withinvertical and horizontal straight bars. In earlier times, however,the splitting of sections of metal was employed to a greater extentthan has been practised since the 18th century, to relieve, orpartially release from parent bars, portions wh ich were fashionedinto decorative features or points of attachment.In the present example this technique has been employed in

the fashioning of the intermed iate bars to achieve a decorativeeffect without resorting to the use of applied embellishments.Splitting is also exploited in the branching leaves of the freely

forged cresti ng.The wavy bars, built up from forged shapes fire welded to-gether, also embody their own decorative elements within thebar without recourse to the ad dition of su pplementary motifs.To achieve the strongest visual effect the frame is constructed

with the broad faces of the bars outwards and the internal barsare secured by means of rivets, which, in themselves, contributesomething of value 1 0 the general effect of the design.1 7


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Lt

I

Fig 17

Fig 18

Fig 19Fig 20

Fig 21

Fig 22

DESIGN 2

The split-forms in the alternate bars are not equally spaced.The intervals between them are carefully proportioned to givelife to the design and avoid a feeling of heaviness.To give a play of light and shade the concave curved sectionsof the wavy bars alternate both horizontally and vertically.

Where dimensions occur in the text they refer specitically tothe example illustrated, the frame of which is made of ;i," .: ~ "bar and measures 3' 3" > : 2' T. These dimensions would, how-ever, be adequate for larger areas, though enlargement wouldtend to lighten the general effec1. This would not necessarily bea disadvantage.

A scale drawing should always be made to confirm the suit-ability of the proportions of the proposed design for any givensite.Assuming that a start is made on the split featuros, a bar, in thisinstance j\" square and long enough for making 'a completeupright to the dimensions given in the working drawing, is cut off.

After marking out the bar is cut with a hot-set almost rightthrough to its other side to the required length.

The work is turned over and the split is completed. It is aelvisableto radius very slightly the corners of the hot-set blade.The split is openeel a little with the hot-set to allow an elongateddrift to be inserted. A bolster is used to avoid damaging the edgeof the hot-set on the anvil face.The split is now ready to accept an elongated drift.The drift and deep bolster with which the next stage of the workis done. See drawings, Figs 46 and 47, page 29.The work is reheated and the drift is driven into the split but notto its full extent.Both faces of the bar are trued with the hand hammer. Afterdressing one face the work is turned over and the other face istreated.18


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Fig. 19

Fig. 21

19

Fig. 18

Fig. 20


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Fig 23

Fig 24

Fig 25

Fig 26

Fig 27

Fig 28

DESIGN 2

The drift is now driven home to its full extent and the truingprocess is completed.To make the diamond shape the split is opened in the middle asa lead-in to the next operation.Another heat is taken and the bar is hammered up from one endto widen out the naturally formed diamond shape to the requiredextent. The effect of the blows should be controlled by turni ngthe work over occasionally. If this poi nt is neglected seriousdistortion may develop and the freshness of the work may belost in course of adjustment.The shape of the diamond feature is now finished on the anvilbick to conform with the contours of the full size working drawing.A delicate touch with the hammer is called for here.To make the circular opening, the initial splitting and dressing iscarried out as before; but the first stage in the actual opening ofthe feature differs.In this case both ends and the centre of the split are widenedby the insertion of the hot-set. This operation predisposes thesplit to assume its final ring-out form.After reheating, the bar is hammered-up from one end and theprocess started in the previous operation is further developed andths split nears its final form.

20


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Fig. 28

Fig. 27


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Fig 29

Fig 30

Fig 31

Fig 32

Fig 33

DESIGN 2

The ring feature is now fully opened across the anvil bick byhammering on each end in turn after heating and reheating.The shape is finally adjusted to conform with the working

drawing.The twisted sections forming part of the embellishment of thesebars are now prepared.The length of the section to be twisted is marked with centre

dots.Top and bottom ~" rope tools are used to indent and round the

bar in such a manner as to convert the square section into aquatrefoil section; thus an assembly of four ,\" round rods issimulated.An increase in length occurs during the operation described inFig 30, owing to the drawi ng 'effect of what is virtually a swagingaction,The prepared section is twisted at a moderate, even, red heat

(see page 46, Fig K of Wrought lronworx) and this processrestores it to approximately the original length.Care is taken throughout to ensure that the twist ends preciselyat its junction with the plain square section of the bar.The successful iorging oi the wally bars calls icr a dishing block,a special tool in the form of a simple die (see drawing, Fig 48, onpage 30). The shape of the die is obtained from the workingdrawing, but to furnish a better idea of what is required a full-scale plasticine model of one of the dished and curvsd shapes isuseful. The impression in the tool is sunk by means of suitableiullers with the mild steel block at a bright heat. A forging is madefrom 1" x j" bar, the ends of which have been reduced androunded leaving a centre swelling. This is the opening move inthe production of one of the component shapes and it is herethat the smith's judgement, as well as measurements, must playan essential part. The forging is left at this stage and retained CoSIRA Publication No. 5~.

22


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Fig. 31

Fig. 33


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Fig 34

Figs 35and 36

Fig 37

Fig 38

Fig 39

DESIGN 2

as a guide. Its value as a final pattern will be checked by theoperations which follow In Figs 34 to 39, and in any of thesesucceeding stages the need for adjustment may be revealed.A handling length of r - . . f' bar is taken and, worki ng to thistrial pattern, the first stage is forged: it is, however, not severedfrom the stock bar.Using anvil horns and scroll wrench the curve is now put in toconform with the impression in the tool.The rectangular section of the blank is transformed into a shallowhalf-rounded section, first by shaping the outer edge with thenormal hand hammer, followed by similar shaping on the inneredge, but this time with the curved faced hammer.With the flat side uppermost the work is now dished in the tool.Suitable fullers are applied progressively rou nd the curve, thesmith's mate striking with moderate blows to avoid undesirablethinning occurring as the form is worked into the cavity.The plane of the forging is trued. The outer edge wilt make con-tact with the anvil face leaving the Inner edge raised naturally.A chalk traci ng of the appropriate portion of the working drawingis prepared on a steel sheet (see Wrought lronwork, pages 12and 13, Figs 12to 15") and the work is now set to follow the linesof this drawing.The freshly forged piece is cut from the bar and work continues

on the making of the requisite number for welding up into adecorative bar.

CoSIRA Publication No. 55.

24


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Fig. 34

Fig. 36

Fig. 38Fig. 39


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Fig 40

Fig 41

Fig 42

Fig 43

Fig 44

DESIGN 2

The forged shapes are fire-welded together with convex andconcave sides alter natinc. In the example shown the weldingprocess was arrested In order to show the position of the scarfs.Nornlilily this weld is completed In one heat and dressed to thecorrect r our d section.

As each weld is finished the work is checked against the chalktracin(_J and set as required.The pairs of branching leaves forming the cresting are forged, inthe present Instance, from 1~" .: - 1 " ; ; " bar.

A heating length of the bar is split to tbe required depth. Thecut is macle oft centre to prouuce lobes of unequal size, to con-form with the ciesign.Immediately in wake of the split the bar is reduced by the use ofa cheese fuller with the work positioned on the anvil bick.The leaf forms are fashioned by short pointing the lobes andcurving the points on the tip of the anvil bick.The leaves are hammer-chamfered on all face side edges. Thisprocess, besides providing the dcsir ed surface texture, alsospreads and s hapas the leaves to conform with the design.

Too great an insistence al precision should be avoided here,as the leaves are freely forged and undue dressing or smoothing01 the sur1aces wil\ destroy their character. A rivet hole is punchedin readiness for fixing the bar on to the frame. The branchingleaves are severed from the haridlinq length leaving a shanklong enough to fire-weld 011 to the top end of a wavy bar.

2 6


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Fig. 42

Fig. 44


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F ig 45

DESIGN 2

All decorative bars are riveted to the frame. The top rivet holesof the wavy bars have been mentioned, leaving the bottom holesand both rivet holes in the other type of bar to be dealt with.In the case of the lower holes in the wavy bars, a swelled eye

was produced at the end of the bar by slot punching and driftingto the appropriate size. The holes in thn other bars are madedifferently. First the ends of the bars are rounded laterally. Afterthe bar end is heated, a round punch with a ir diameter flat faceis po sitioried on the end of it. The punch is dealt a heavy blow bythe smith's mate using a sledge hammer, and produces a flatround boss stepped-in from the face side of the bar, with an areaand section of sufficient strength to permit the drilling of a rivethole. If it is desired, distinction may be added to the riveting bossby a slight and graceful reduction of the square bar immediatelyadjacen t to the boss. Thi s refinement shou Id, of course, be madeover the anvil bick with the curved faced hammer before the bossis formed. Both operations described cause the bar to lengthena little, consequently a reduction must be made prior to cuttingaway surplus bar at each end.

Fig. 45


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B

6ECTION &-8Fig. 46 Elongated drift

f- s 1 2 0 : -lP L II. N

G----,JSIO[ VIEW

Fig. 47 Deep bolster

" +

SECTIONA-A

. 11


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'leTION A-A

30

7

PLAN OF TOP

PLAN OF !.OlTOMA l--_ --~--------

A J 'I.""_- $_'__~----+t:.5"IOf. VIEW

Fig.48 Dishing blocK


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Design 3This is an example at the time-honoured quatrefoil theme but onein which the decorative elements are formed almost entirely bymeans of a splitting technique.Curved spurs, relieved from the bars by chiselling, form sectionsof each quatrefoil, leaving the parent bars with modified contourswhich playa part in the decorative whole at the points of inter-section.The 0uter frame is of interest because it contri butes to the

completion of the pattern and thus performs rather more than theusual structu ral function.Ironwork in which this type of construction has been used does

not entirely rely for its appeal on flow of line, and a silhouetteeffect. The surface of the metal acquires an attractive texturalquality during forging, while chamfered edges, offset sectionsand rivet heads break up the play of light over the surface of thework and enhance the general effect.The dimensions of this grille are 2' 4~" :-: l' 71/'.

3 1


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Fig 49

Fig 50

Fig 51

DESIGN 3

The pair of tools illustrated are used for offsetting the 1" x i"bars at the intersecting points and junctions with the frame.The guide pegs of the tool have been set at a distance whichwill just allow the bar to be moved freely through the tool without

binding.The bars are marked out in this instance at 4~' centres and

accurate positioning in the tool is ensured by aligning each centreas work proceeds with punch marks indicating the centre lineof the bottom tool.

At a bright red heat the bar is positioned between the top andbottom tools and two or three light blows are sufficient to seatthe heated metal in the bed of the bottom tool.Excessive hammering must be avoided as this will lengthen

the distance between centres, whereas these distances willremai n unchanged if moderate controlled blows are used.

When marki ng out the section of bar from which the spurs arereleased it is essential to remember that all the natural chamferingleft by the chisel cuts must be seen on one side of the work only,the face side.It follows that the horizontal and vertical bars are not marked

out on the same side, since the offsets are somewhat akin tohalvings. Assu ming that the horizontal bars are marked out withthe impressed offset sections in a downward poaition, thevertical bars must then be marked out on the opposite side, thatis, with the impressed offsets in a raised position. (See thisfigure and Design, 4, Fig 67, page.)The scheme of marking out is dictated by the fact that adequate

sections of metal must be relieved from the bar in order to formthe tapered quatrefoil sections but yet, at the same time, sufficientsubstance must be left in the parent bar to satisfy both structuraland visual requirements.The width of the bar is divided equally into three and the mark-

ing completed as shown in Fig 60 preparatory to hot chiselling.The essential points which determine the chiselling positions aremarked with a centre punch. Two specially forged chisels areneeded, one of each hand. (See drawing, Fig 62, page 39.)32


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The cut is made right through the hot metal from the face sideonly.The cutting edge of the chisel is of the precise length and of the

correct shape for the cut required. It must therefore be placedaccurately and struck decisively. There is no room for fumbli ng.A vessel contain ing water, in which the chisel may be cooledat intervals, must be within convenient reach.A copper or soft iron plate mus! be used under the work toprotect the edge of the tool from the anvil face.A very slight lengthening of the parent bar takes place d uri ngthis hot splitting process, which collectively affects the overalllength of any given bar. The amount of lengthening can only bedetermined by making a short trial section.

Fig. 4 9

Fig. 51

Fig 52

33

Fig. 52


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Fig 53

Fig 54

Fig 55

Fig 56

Fig 57

DESIGN 3

A t a red heat the work is engaged between anvil horns of thecorrect size (see d rawi ng, Fig 63, page 39), and with the round-nosed pliers the spurs are moved away from the parent bar.

Using a stake (see drawing, Fig 64, page 40) specially designed toenable a number of operations to be done withi n a small compass,and a 'fuller' ended hammer (see drawing, Fig 65, page 41), a spuris drawn out to form part of the crescent shape which, with itspair, makes one quarter of a quatrefoil. When the smith's handis lower than the part being forged, an old woollen glove is wornto ward off hot scale.Since the section of the spur is not, at this juncture, square,

and since the bevel left by the chisel must coincide with the faceof the special stake during forging, distortion of the spur isinevitable.

If the work is viewed edgeways any distortion is readily seen andit must be dealt with in the course of forging.

The first stage in correcting distortion is carried out on the man-drel section of the special stake using the same hammer, theother end of which has been forged and ground to a flat squareface.The work is tilted at an angle and with well controlled blows

the high edge of the spur, thrown into prominence in this position,is forged down from tip to root. By this means the spur is giventhe desired square section.

The spur-one only is dealt with at a time--is broug ht back intoa plane true with the parent bar and its surface is levelled in oneand the same operation. Th is work is done on the anvil-like surfaceof the multiple tool and, as in the three preceding operations, thelength of the spur is increased.When the forging of a pair of spurs has reached this point,

a full quarter of a quatrefoil has been formed, and the tips shouldbe long enough to connect with their neighbours when the grilleis assembled.

34


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Fig. 53

Fig. 55

Fig . 57

Fig .. 5 4


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Fig 58

Fig 59

DESIGN 3

In the final setting operation another special tool IS brought intoplay (drawing, Fig 66, page 42).This tool comprises a crescent-shaped former and four guide

pegs spaced to accept the cut-away stem bearing the quatrefoilsections.With the work at a red heat, and using a pai r of ro und-n osed

pliers In each hand, the horns of the crescents are squeezed intoshape against the former.

Providing that the offsets have been accurately positioned an dthat the correct reductions have been made between centres toallow for the slight lengthening which occurs during hot splitting,the assembly of the grille is straightforward.As the frame bars bear crescent shapes on their inner edges

only, they will not tend to lengthen as much as the internal bars,and therefore it is advisable to mark oft the centres of their offsetsections at the finishing intervals, i.e., the interval given by theworking drawing.Small, unpredictable variations can occur occasionally between

centres in forgings of this kind, which must be adjusted prior tofi nal assembly. Such adjustments may be effected by lengtheningby the drawing process or shortening by upsetting, whichever isappropriate tor the correction of the faulty sectio ns.T he bars are straightened and any twists are removed I after

which the rivet holes are drilled in the bars forming the outerframe.The frame is temporarily bolted together at the fa ur corners and

tested for squareness.The horizontal and vertical bars are now laid one at a time on

the frame and the positions of their end holes are scribered oftand drilled.One set of bars, either vertical or horizontal, are now drilled

at the points of intersection.The grille is temporarily bolted together and the position s of

the holes in the set of undrilled bars are scribered through,dri lied and replaced in position.At this stage, with frame and bars bolted together and again

36


37/42

tested for squareness, any overlapping of the quatrefoil segmentsis corrected with a small scroll wrench.Small, final adjustments to the tips of the segments are made

after the temporary bolts have been withdrawn singly and re-placed with rivets.If it is found necessary to resort to the use of heat the oxy-

acetylene torch is employed.

Fig. 58

Fig. 5 9

37


38/42

II I \ . . . J. .J . J I I ";':I I I! I I I ~J. .. L I1 I I II I' . . . . . . . . I I ''l!I I IT! - I' 1 f-- I'/,' 1 I/, 1'1. I , . -l'1

+ - 4~'. .r__/ , ./ '------._;;;

Fig, 60 Marking out diagram

--------.-.-----------------

rorrol~'l.A" .-" ~.

38

I~I" I1_ { T' 1;

T

' .

It H D V I ('"

Fig, 61Offsetting tools


39/42

,/. .Iii 'II~ I;;=:-,

f======-----~ T : . u~L

1 O ' /a '

.r" : : 1

PLio >j 0'C:U TT ,>jGEDGE

PLio,. OFCUTTING~OGE

Fig. 62 Special chisels-one of each hand

I L .i. ..

Fig. 63Anvil horns1INO v Ir .. 1-1 D I_ vr [W

39


40/42

z~,_~ u'",~ :z, .0

t~i . , . . , 5. .T .. . ~.( - , I ~ . ;,~ ZI- 0U >-. . . ~~ . . . ."

>

zQ' "

Fig. 64 Multi-purpose stsk

40


41/42

.~0

41

P LAN

(\I

\" \

Fig . 65 Double-ended hammer

o


42/42

{ 0 .~ ~"J "'l0 0

DESIGN 3

IIi1

SIOEVLEW

PLA.N

FII}. 66 Jig for setling spurs

Documents

Decorative Ironwork Part 1_tcm2-18947